If you're ever likely to suffer from Acrophobia (from the Greek: akron , meaning "peak, summit, edge" and phobos, "fear" and meaning an extreme or irrational fear of heights), then Sears Tower in Chicago is the place that'll surely bring it on. Standing at 1,450 feet and 110 stories, Sears Tower is the tallest building in North America and the third tallest building in the world. The building recently added a new attraction as part of an updated Skydeck Chicago experience. Christened “The Ledge”, it's a series of glass bays on the 103rd floor that offer visitors unobstructed views of Chicago – 1,353 feet straight down.